Growth morphology is an important factor affecting fermentation of filamentous fungi during production of proteins and fine chemicals. cot-1 of Neurospora crassa is a colonial temperature sensitive mutation that has been described in detail Steele, et al., Arch. Microbiol. 113:43 (1977) and Collinge, et al., Trans. Br. Mycol. Soc. 71:102 (1978)). Germination and growth of the mutant is normal at 26° C., but a shift to 37° C. causes the cessation of hyphal tip extension, and emergence of lateral branches at an abnormally high frequency to give hyperbranching germlings. An increase in the frequency of septation is also seen. Sequence analysis indicated the gene product belongs to the family of serine/threonine protein kinases (Yarden, et al., EMBO J. 11:2159 (1992). These kinases act in signal transduction pathways, but how cot-1 is integrated into the pathway(s) controlling hyphal growth polarity has yet to be elucidated. The specific mutation that causes the temperature sensitivity in N. crassa cot-1 has been found to be a histidine to arginine substitution (Gorovits, et al., Fungal Genetics and Biol. 27:264 (1999).
There remains a need in the art for genes that control growth morphology in filamentous fungal cells, like Trichoderma and Aspergillus, that are used as a source of recombinant proteins in an industrial setting and to enhance the production of proteins and fine chemicals. This invention meets this need as well as others.